Broken eggs?

Two of the three brown eggs we've gotten have been cracked. One was laid in the middle of the coop so I figured it was a fluke first egg thing. She just didn't know what to do so the egg fell to far and cracked.

Today, it was in the nest and the end was cracked.

I just gave them oyster shell today, do you think that's the problem? My girls have only been laying a week or so...is it a newbie problem?